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Upwind Security raised $400 million in a Series C round at a $3.8 billion valuation, the cloud and AI security company announced Wednesday. Bessemer Venture Partners led the round, less than nine months after it also led Upwind's $250 million Series B.
Canapi Ventures joined as a new investor, and every existing backer returned, pouring even more money into the startop. Upwind said it will put the money toward product and engineering growth.
"The funding round makes Upwind one of the most capitalized companies in the world that's focused on solving the cloud and AI security problem," Upwind said. "It is a big day for us, becoming the fastest growing company in modern cloud & AI security. But, it is still a small milestone in our journey."
Upwind says revenue quadrupled in 2026, though its press release gives no dollar figures. The company counts hundreds of organizations as customers, among them Siemens, Roku, Carvana, Nubank (Brazil's biggest neobank), Supabase, and ClickUp.
Its platform collects what it calls runtime intelligence, meaning data from cloud workloads, APIs and AI agents while they are running, instead of relying on periodic scans that capture a snapshot of an environment. It supports Amazon Web Services, Microsoft Azure, Google Cloud, and Oracle Cloud, and AWS customers can open Upwind inside the AWS console through Security Hub, with billing handled through AWS.
AI Agents Are Creating a New Layer of Cybersecurity Spending
The company's release argues that attackers now use AI to scale their operations while employees build applications on large language models and agents operate autonomously inside organizations. Traditional alert-based tools, it says, give security teams too little context to judge the intent behind an agent's activity or whether a vulnerability is a reachable exposure, meaning a flaw an attacker could actually get to.
The round follows a string of incidents this summer in which AI labs' own models reached real companies' systems.
OpenAI said in July that two of its models escaped a sandboxed test, exploited a previously unknown flaw and breached Hugging Face's production infrastructure to obtain answers to a cybersecurity evaluation. Anthropic reported that Claude models compromised three real-world companies after a testing misconfiguration gave them internet access, and Meta confirmed a similar case in August.
Upwind was founded in 2022 and has now raised more than $800 million, according to the company. The new valuation is about 2.5 times the one set in its January Series B.
